Rare earth metals

Rare earth metals are a relatively small group of elements, with a total of 17 representatives. They are all substances of a silvery white color.

Rare earth elements and the history of their discovery

This group of substances was discovered relatively recently. The samples were first discovered in 1794. At that time, a chemist from Finland, Yukhan Gadolin, investigated samples of ore near the town called Ytterby. Here he discovered an unknown "liquid earth", which he then named in honor of the location - yttrium. After some time, the samples were again examined by Martin Klaport, who isolated an additional substance called cerium in honor of the planet Ceres.

And by 1907, 14 such elements had already been discovered.

The very name "rare earth metals" was introduced in the late 18th century. Here played the role of the fact that all elements of this group form refractory oxides, which practically do not dissolve in water. In addition, scientists of the time mistakenly believed that these metals are rarely found in the earth's crust.

Rare earth metals: group representatives

As already mentioned, this group consists of 17 chemical elements. These include:

• Lanthanum.
• Cerium (named after the planet Ceres).
• Neodymium.
• Predeoizim.
• Samarium.
• Promethium.
• Gadolinium.
• Europium.
• Terbium.
• Holmium.
• Dysprosium.
• Erbium.
• Ytterbium.
• Lutetium.
• Thulium.

It is interesting that the outer electronic levels of these atoms are practically the same. It is with this that the chemical and physical properties of metals are related.

Rare earth metals and their chemical properties

Representatives of this group have a fairly high reactivity, which is particularly high when heated. For example, at elevated temperatures some metals are able to react with hydrogen.

In addition, when heated, these elements react with oxygen to form persistent, water-insoluble oxides. By the way, when burning metals in atmospheric oxygen, a significant amount of heat is released. It is for this group that pyrophoricity is characteristic - the property of sparking in the air.

Rare earth metals can also form hydroxides, which are poorly soluble in water and possess some amphoteric properties.

Practically for all members of the group, the degree of oxidation +3 is characteristic. The activity of elements is not the same. The most active is lanthanum.

Extraction of rare earth metals

In most cases, rare-earth metals are found together. In one sample of the rock there are several representatives of the group. To date, more than 250 minerals are known, in which rare-earth elements are present. The main minerals include monazite, parisite xenity, orthite.

The most common substance in the earth's crust is cerium. But thulium and lutetium in nature are the least.

In 2008 around 124 thousand tons of rare earth metals were mined. Leaders in this production were countries such as India, China and Brazil.

Another place of extensive deposits of rare earth metals was discovered in 2011. These territories are at the bottom of the Pacific Ocean, near the Hawaiian Islands, French Polynesia and Tahiti.

Rare earth metals and their application

These elements are used in completely different industries. For example, they are widely used in the glass industry. First, they increase the translucence of the glass. Secondly, these metals are used for the production of special glass - glass, absorbing ultraviolet rays or transmitting infrared cures. With the help of rare-earth substances, heat-resistant glass is produced.

In oil refining, these elements act as catalysts. They are also used in the chemical industry to produce high-quality paints, varnishes and pigments.